1. Field of the Invention
The present invention relates to a car theft alarm system or an antitheft system for generating an alarm when the vehicle is about to be stolen by unlawful operation.
2. Description of the Prior Art
Vehicle theft alarm apparatuses have conventionally been conceived for preventing the vehicle or the equipment mounted thereon from being stolen. In these apparatuses, a certain operation of the driver places the vehicle on vigilance or armed state. Under this vigilance state, if the vehicle door or bonnet being opened is detected, a large buzzer sound or the like alarm is issued to give warnings to related persons. An example of such apparatuses is disclosed in JP-A-57-104439.
In conventional apparatuses, once the power line between the apparatuses and a car power supply is disconnected, it is impossible to issue a proper alarm even if it is reconnected.